KR20100055398A - Microresonator system and methods of fabricating the same - Google Patents

Abstract

Various embodiments of the present invention are related to microresonator systems that can be used as a laser, a modulator, and a photodetector and to methods for fabricating the microresonator systems. In one embodiment, a microresonator system comprises a substrate (106) having a top surface layer (104), at least one waveguide (114,116) embedded within the substrate (106), and a microdisk (102) having a top layer (118), an intermediate layer (122), a bottom layer (120), current isolation region (128), and a peripheral annular region (124,126). The bottom layer (120) of the microdisk (102) is in electrical communication with the top surface layer (104) of the substrate (106) and is positioned so that at least a portion of the peripheral annular region (124,126) is located above the at least one waveguide (114,116). The current isolation region (128) is configured to occupy at least a portion of a central region of the microdisk and has a relatively lower refractive index and relatively larger bandgap than the peripheral annular region.

Description

Micro resonator system and its manufacturing method {MICRORESONATOR SYSTEM AND METHODS OF FABRICATING THE SAME}

Embodiments of the present invention relate to microresonator systems, and more particularly, to microresonator systems that can be used as lasers, modulators, and photodetectors, and to a method for manufacturing these systems.

Recently, the increased density of microelectronic devices on integrated circuits has caused a technical bottleneck in the density of metal signal lines that can be used to interconnect these devices. In addition, the use of metal signal lines causes a significant increase in power consumption and difficulty in synchronizing the longest links located on top of most circuits. Instead of transmitting information as electrical signals over signal lines, the same information is encoded in "electomagnetic radiation" and the optical fibers, ridge waveguides and photonic crystal waveguides. May be transmitted over the waveguides. Transmitting encoded information to the ER via waveguides has a number of advantages over transmitting electrical signals over signal lines. First, degradation or loss is much less for ER transmitted through waveguides than for electrical signals transmitted through signal lines. Second, waveguides can be fabricated to support much higher bandwidths than signal lines. For example, a single Cu or Al wire may transmit only a single electrical signal, but a single optical fiber may be configured to transmit approximately 100 or more differently encoded ERs.

Recently, advances in materials science and semiconductor fabrication techniques have developed photonic devices that can be integrated with electronic devices, such as CMOS circuits, to form "PICs" (photonic integrated circuits). Made it possible. The term “photonic” refers to devices capable of operating with a classically characterized ER or quantized ER having frequencies that span the electromagnetic spectrum. PICs are photonic equivalents of electronic integrated circuits and can be implemented on a wafer with semiconductor material. In order to efficiently implement PICs, passive and active photonic components are required. Waveguides and attenuators are generally passive photos that can be manufactured using conventional epitaxial and lithographic methods and can be used to direct the propagation of the ER between microelectronic devices. Nick components are examples. Physicists and engineers have realized the need for active photonic components that can be used in PICs.

Various embodiments of the present invention relate to microresonator systems including microdisks that can be used as lasers, modulators, and photodetectors, and methods for manufacturing such microresonator systems. In one embodiment of the invention, a micro resonator system includes a substrate having a top surface layer, at least one waveguide embedded within the substrate and positioned adjacent to the top surface layer of the substrate, and a top layer, an intermediate layer, a bottom layer, a current insulating region, And a micro disk having a peripheral annular region. The bottom layer of the micro disk is attached to and in electrical communication with the top surface layer of the substrate and positioned such that at least a portion of the peripheral annular region is disposed over the at least one waveguide. The current isolation region is configured to occupy at least a portion of the central region of the micro disc and has a relatively low refractive index and relatively large bandgaps than the peripheral annular region.

1A illustrates an isometric view of a first micro resonator system in accordance with embodiments of the present invention.
FIG. 1B illustrates a cross-sectional view of the first micro resonator system across line 1b-1b, shown in FIG. 1A, in accordance with embodiments of the present invention. FIG.
2 illustrates a cross-sectional view of layers including an exemplary micro disk in accordance with embodiments of the present invention.
3A-3B show hypothetical plots of electron bandgap energies for the peripheral and current isolation regions of the micro disc shown in FIG. 1.
4A illustrates a path of current flow in a micro disk of the first micro resonator system, shown in FIG. 1, in accordance with embodiments of the present invention.
4B illustrates a substantial confinement of whispering gallery mode (WGM) to peripheral regions of the micro disk of the first micro resonator system, shown in FIG. 1, in accordance with embodiments of the present invention.
5A illustrates an isometric view of a second micro resonator system in accordance with embodiments of the present invention.
5B illustrates a cross-sectional view of a second micro resonator system across line 5b-5b, shown in FIG. 5A, in accordance with embodiments of the present invention.
FIG. 6A illustrates paths of current flow in the micro disk of the second micro resonator system, shown in FIG. 5, in accordance with embodiments of the present invention. FIG.
FIG. 6B illustrates the substantial confinement of the WGM to peripheral regions of the micro disk of the second micro resonator system, shown in FIG. 5, in accordance with embodiments of the present invention.
FIG. 7A shows an energy level diagram associated with quantized electron energy states of a quantum well-based gain medium.
FIG. 7B shows a schematic representation of the first micro resonator system, shown in FIG. 1, operated as a laser in accordance with embodiments of the present invention. FIG.
8A shows a schematic representation of the first micro resonator system, shown in FIG. 1, operated as a modulator in accordance with embodiments of the present invention.
8B shows a plot of intensity versus time of unencoded ER.
8C shows a plot of intensity versus time for data encoded ER.
9 shows a schematic representation of the first micro resonator system, shown in FIG. 1, operated as a photodetector in accordance with embodiments of the present invention.
10A-10K illustrate isometric views and cross-sectional views associated with a method of manufacturing a first micro resonator system, shown in FIG. 1, in accordance with embodiments of the present invention.
11A-11B illustrate cross-sectional views associated with a method of manufacturing a second micro resonator system, shown in FIG. 5, in accordance with embodiments of the present invention.

Various embodiments of the present invention relate to microscale resonator (“micro resonator”) systems and methods for manufacturing micro resonator systems including micro discs that can be used as lasers, modulators, and photodetectors. In the various micro resonator system embodiments described below, multiple structurally similar components containing the same materials have been given the same reference numerals, and for brevity, the description of their structure and function is not repeated.

1A shows an isometric view of a micro resonator system 100 in accordance with embodiments of the present invention. The micro resonator system 100 includes a micro disk 102 attached to the upper surface layer 104 of the substrate 106, a first electrode 108 attached to the upper surface 110 of the micro disk 102, and an upper portion. And a second electrode 112 attached to the surface layer 104 and positioned adjacent to the micro disk 102. The micro disc 102 is a micro resonator of the micro resonator system 100 and can be configured to support certain WGMs. The substrate 106 includes two waveguides 114 and 116 extending through the substrate 106 and positioned adjacent to the top surface layer 104. Waveguides 114 and 116 are disposed directly below at least a portion of the peripheral annular region of micro disk 102. The micro disc 102 includes an upper layer 118, a lower layer 120, and an intermediate layer 122 sandwiched between the upper layer 118 and the lower layer 120. Lower layer 120 may be composed of the same material as upper surface layer 104, as described below with reference to FIG. 1B. The layers 118, 120, and 122 of the micro disc 102 are described in more detail below with reference to FIG. 2.

FIG. 1B illustrates a cross-sectional view of the micro resonator system 100 across line 1b-1b, shown in FIG. 1A, in accordance with embodiments of the present invention. As shown in FIG. 1B, the waveguides 114 and 116 are disposed just below the portions 124 and 126 of the peripheral annular region of the micro disk 102. The micro disk 102 includes a current isolation region 128 that is configured to occupy at least a portion of the central region of the micro disk 102. The second electrode 112 is in electrical communication with the lower layer 120 through the upper surface layer 104. Although only one second electrode 112 is disposed on the top surface layer 104 of the substrate 106, in other embodiments of the invention, two or more electrodes may be located on the top surface layer 104. Can be.

Note that the micro resonators of the micro resonator system embodiments of the present invention are not limited to circular-shaped micro disks, such as micro disk 102. In other embodiments of the invention, the micro disk 102 may be circular, elliptical, or have any other shape suitable for supporting WGM and generating a resonant ER.

Upper layer 118 may be a III-V semiconductor doped with an electron acceptor dopant, referred to as a " p -type semiconductor," and lower layer 120 may be referred to as an " n -type semiconductor." The haze may be a III-V semiconductor doped with an electron donor dopant, where the Roman numerals III and V refer to elements of groups 3 and 5 of the periodic table of elements. Interlayer 122 includes one or more quantum wells. Each quantum well may be a relatively thin III-V semiconductor layer sandwiched between two layers of different types of III-V semiconductors. 2 illustrates a cross-sectional view of layers including micro disk 102 in accordance with embodiments of the present invention. In FIG. 2, top layer 118 may be p -type InP, where Zn may be used as dopant, and bottom layer 120 may be n -type InP, where Si may be used as dopant. Interlayer 122 includes three quantum wells 201-203, In _x Ga _{1 - x} As _y P _{1 -y} , where x and y range between 0 and 1. Interlayer 122 also includes barrier layers 205-208 of In _x Ga _1-x As _y P _1-y , where x and y range between 0 and 1. The selection of parameters x and y is done to lattice match adjacent layers and this is known in the art. For example, for layers lattice matched to InP layers 118 and 120, the x value is chosen to be 0.47. The choice of y determines the bandgap energy of the quantum well. The operation of the quantum well is described below with reference to FIG. 7A. Quantum wells 201-203 can be configured to emit ER at the desired wavelength λ, while barrier layers 205-208 are carriers (ie, electrons and holes) injected into the quantum well. Can be configured to have a relatively larger bandgap. Layers 205 and 206 separate quantum wells 201-203, and layers 207 and 208 separate two quantum wells 201 and 203 from layers 118 and 120, respectively. Thicker layers. Substrate 106 may be composed of SiO ₂ , Si ₃ N ₄ , or another suitable dielectric insulating material. Waveguides 114 and 116 may be composed of Group IV elements, such as Si and Ge. In other embodiments of the present invention, other suitable III-V semiconductors such as GaAs, GaP and GaN may be used.

The current isolation region 128 has a relatively larger electron bandgap than the quantum well electron bandgaps associated with the peripheral annular region of the micro disk 102. 3A shows a plot of electron bandgap energies vs. microdisk 102 height z for three quantum wells of peripheral regions of microdisk 102. The electron bandgap energies associated with the lower layer 120 and the upper layer 118 are represented by ΔE _B and ΔE _T , respectively. The quantum wells of the intermediate layer 122 have bandgap energies ΔE _QW , and the barrier layers adjacent to the quantum well layers have a larger bandgap energy ΔE _Bar . The bandgap energies ΔE _T and ΔE _B correspond to the bandgaps, which correspond to layers 118 and 120 forming a double heterojunction barrier for constraining electrons and holes to the intermediate layer 122. Note that it is greater than the energy ΔE _Bar . FIG. 3B shows a plot of electron bandgap energies versus microdisk 102 height z for current isolation region 128 of microdisk 102. As shown in FIG. 3B, the current isolation region 128 removes bandgap energies associated with the quantum well layers and barrier layers of the intermediate layer 122, or is represented by dashed energy levels 302 and 304. As is uncertain.

The difference between the current isolation region 128 and the electron bandgap energy associated with the peripheral region of the micro disk 102 substantially binds the current to the paths of the peripheral region when a voltage is applied to the electrodes 108 and 112. It can be used to. 4A shows a path 402 representing the flow of current between electrodes 108 and 112 in accordance with embodiments of the present invention. Path 402 bends near the higher bandgap current isolation region 128 when connecting electrodes 108 and 112. The current can be substantially confined to the peripheral regions of the micro disk 102, such as the peripheral region 126, as follows. Consider applying a voltage to the electrodes 108 and 112 that is greater than the electron bandgap energies associated with the peripheral annular region but does not exceed the electron bandgap energies associated with the current isolation region 128. Because the voltage is large enough, current can flow through the peripheral region 126, but current cannot flow through the insulating region 128. In other words, the current can be substantially confined to the peripheral region 126 using voltages that are relatively lower than the voltages needed for the current to flow through the current isolation region 128. Current paths, such as path 402, that circumvent current insulating region 128 represent lower energy paths through which current flows between electrodes 108 and 112.

In general, because a micro resonator has a greater overall index of refraction than those surrounding it, the ER transmitted in the micro disc is generally trapped as a result of total internal reflection near the circumference of the micro disc. The modes of the ER captured near the boundaries of the microdisc are called "whispering gallery modes". The WGM has a specific resonant frequency λ related to the diameter of the micro disc. However, in the case of a general micro disk, there are other modes that do not bind the ER near the perimeter in the form of WGM.

Since the current insulating region 128 has a relatively wider bandgap and a relatively lower refractive index than the peripheral regions of the micro disk 102, the micro disk 102 embodiments of the present invention are described in detail. It can be used to substantially bind the ER to the surrounding areas. 4B illustrates the substantial confinement of the WGM to peripheral regions of the micro disk 102 in accordance with embodiments of the present invention. As shown in FIG. 4B, the top view 404 of the micro disc 102 includes directional arrows located along the boundary of the micro disc 102. The directional arrows indicate the propagation direction of the hypothetical WGM propagating near the boundary of the micro disc 102, and the length of the directional arrows corresponds to the wavelength λ of the WGM. Intensity plot 406 represents the intensity distribution versus distance of the WGM across line A-A in top view 404. Dotted line intensity curves 408 and 410 represent a substantially constrained WGM near the boundary of micro disk 102. Portions of the curves 408 and 410 that extend beyond the diameter of the micro disk 102 represent the evanescence of the WGM along the boundaries of the micro disk 102. Sectional view 412 shows portions 124 and 126 of the peripheral annular area occupied by the WGM. Dotted ellipses 414 and 416 represent the evanescent coupling of the WGM to waveguides 114 and 116. The current isolation region 128 thus provides both current and light isolation since the ER will be bound to a region of higher refractive index.

5A shows an isometric view of a second micro resonator system 500 in accordance with embodiments of the present invention. The micro resonator system 500 has a first electrode 108 replaced with a microring electrode 502 and adjacent to the micro disk 102 to the top surface layer 104 of the substrate 106 (shown). Same as the micro resonator system 100, shown in FIG. 1, except that a third electrode is disposed. 5B illustrates a cross-sectional view of a micro resonator system 500 across line 5b-5b, shown in FIG. 5A, in accordance with embodiments of the present invention. As shown in FIG. 5B, the microring electrode 502 is located over and covers at least a portion of the top surface of the micro disk 102. The third electrode 504 is positioned adjacent the micro disk 102 and is in electrical communication with the lower layer 120 through the upper surface layer 104.

Since the microring electrode 502 is disposed over a portion of the peripheral region of the micro disk 102, the flow of current between the microring electrode 502 and the electrodes 112 and 504 is the path 402 shown in FIG. 4A. Take a more direct path than 6A shows paths 602 and 604 showing the flow of current between microring electrode 502 and electrodes 112 and 504 in accordance with embodiments of the present invention. Paths 602 and 604 represent more direct or lower resistance paths than path 402 through which current flows between microring electrode 502 and second and third electrodes 112 and 504. As shown in FIG. 6B, the substantial bondage of the WGM to the peripheral region of the micro disk 102 and the attenuation coupling of the WGM to the waveguides 114 and 116 are the same as described above with reference to FIG. 4B.

The micro disk 102 can be used as a laser to generate a coherent ER transmitted in the waveguides 114 and 116. The laser has three basic components: gain medium or feedback of the ER in the amplifier, pump, and optical cavity. The quantum wells of the interlayer 122 comprise a gain medium, the current or voltage applied to the electrodes 108 and 112 is a pump, and the WGM produced by pumping the quantum wells of the interlayer 122 is a micro disk 102. Feedback propagates by total reflection when propagating near the boundary of.

)를 갖는 비교적 더 넓은 영역들(704 및 706)은 양자 우물을 둘러싼 벌크 재료에 대응한다. 도 7a에 도시된 바와 같이, 양자 우물은 컨덕션 밴드에서 정공 에너지 레벨(708) 및 밸런스 밴드에서 세 개의 전자 에너지 레벨들(710-712)을 갖는다. 이득 매질이 반도체 재료를 포함하기 때문에, 전기적 펌핑과 같은, 적절한 전자 자극은 전자들을 밸런스 밴드로부터, 정공 에너지 레벨(708)과 같은, 컨덕션 밴드의 양자화된 레벨들로 촉진시킨다(promote). 밸런스 밴드에서 정공과 전도하는 전자의 자발적인 재결합은 hc /λ에 의해 주어지는 에너지를 갖는 광자의 방출을 발생시키는데, 여기에서 h는 플랑크 상수이고, c는 진공에서 ER의 속도이다. 유도 방출(stimulated emission)은 동일한 에너지 또는 파장에서 더욱 많은 광자들을 생성하도록 이득 매질을 자극하는 WGM의 광자들의 결과로서 발생한다. 유도 및 자발 방사성 방출들 양쪽 모두에서, 방출된 ER의 에너지는:The gain medium may consist of at least one quantum well having a suitable bandgap. The quantum well size and the bulk material surrounding the quantum well determine the energy level spacing of the electronic states of the quantum well. In general, a quantum well is configured to have a relatively small number of quantized electron energy levels in the balance band and some quantized hole energy levels in the conduction band. Electrons that transition from the lowest energy levels of the conduction band to the energy levels of the balance band determine the emission wavelength [lambda] of the gain medium. 7A shows an energy level diagram 700 associated with quantized electron energy states of a quantum well-based gain medium of width a. The narrower region 702 with the bandgap energy E _g corresponds to the quantum well and the bandgap energy (

Relatively wider areas 704 and 706 with) correspond to the bulk material surrounding the quantum well. As shown in FIG. 7A, the quantum well has a hole energy level 708 in the conduction band and three electron energy levels 710-712 in the balance band. Because the gain medium comprises a semiconductor material, suitable electron stimulation, such as electrical pumping, promotes electrons from the balance band to quantized levels of the conduction band, such as the hole energy level 708. Spontaneous recombination of holes and conducting electrons in the balance band results in the emission of photons with energy given by hc / λ , where h is Planck's constant and c is the velocity of ER in vacuum. Stimulated emission occurs as a result of the photons of the WGM stimulating the gain medium to produce more photons at the same energy or wavelength. In both induced and spontaneous radioactive emissions, the energy of the released ER is:

Where E ₂ is the energy level 708 of the electrons pumped into the conduction band and E ₁ is the energy level 710 associated with the holes in the balance band that combine with electrons from the conduction band. As long as the electrical pump is applied to the gain medium, the feedback caused by total reflection in the micro disk 102 causes the strength of the WGM to increase. Lasing occurs when the gain is equal to a loss inside the micro disc 102. The micro disc 102 forms an optical cavity with gain, and the waveguides 114 and 116 connect the ER to the outside of the micro disc 102.

FIG. 7B shows a schematic representation of the first micro resonator system, shown in FIG. 1, operated as a laser in accordance with embodiments of the present invention. As shown in FIG. 7B, electrodes 108 and 112 are connected to current source 710. The quantum-well layers of the micro disk 102 can operate as a gain medium by pumping the micro disk 102 with the appropriate magnitude of current supplied by the current source, as described above with reference to FIG. 7A. As a result, a WGM having a wavelength lambda is generated in the micro disk 102, and total internal reflection causes the WGM to propagate near the boundary of the micro disk 102 when the intensity of the WGM increases. The WGM is attenuatedly coupled to the waveguides 114 and 116, resulting in an ER having a wavelength λ propagating in the waveguides 114 and 116.

FIG. 8A shows a schematic representation of the micro resonator system 100, shown in FIG. 1, operated as a modulator in accordance with embodiments of the present invention. Current source 710 is connected to data source 802, which may be a central processing unit, a memory, or another data generation device. ER source 804 is coupled to waveguide 116 and emits an ER having a substantially constant intensity over time, as shown in FIG. 8B. Referring again to FIG. 8A, the amount of ER connected to the micro disk 102 depends on the detuning, coupling coefficient, and losses inside the micro disk 102. When the wavelength λ of the ER emitted by the source 804 is detuned from the resonance of the micro disc 102, the ER is not connected from the waveguide 116 to the micro disc 102. When the wavelength λ of the ER is in resonance with the micro disk 102, the transmission of the ER propagating in the waveguide 116 is reduced because the ER is attenuatedly coupled to the micro disk 102 to produce a WGM. A portion of the ER transmitted in the waveguide 116 propagates in the peripheral region as a WGM having a wavelength λ, which is attenuatedly connected to the peripheral region of the micro disk 102 disposed over the waveguide 116. Data source 802 encodes data in the WGM by modulating the magnitude of the current generated by current source 710. Modulating the magnitude of the current transmitted between the electrodes 108 and 112 causes the refractive index of the micro disk 102 to change correspondingly. When the refractive index of the micro disc 102 changes, the resonant wavelength of the micro disc 102 changes, resulting in detuning from the resonant wavelength of the ER transmitted in the waveguide 116. This modulates the transmission of the ER from the waveguide 116 to the micro disk 102 and then modulates the strength of the ER transmitted from the waveguide 116. When waveguide 114 is present, ER may be transmitted from input waveguide 116 to waveguide 114 via micro disk 102. The amount of ER transmitted to waveguide 114 depends on the bond strength. Modulating the refractive index of the micro disk 102 causes a reduction in the intensity of the ER transmitted to the waveguide 114. By adjusting the loss inside the microring 102, the strength of the ER in the waveguide 116 can also be modulated. This is accomplished by using a quantum confined stark effect that modulates the bandgap of the quantum well through the application of an applied voltage. Increasing the loss in the micro disk 102 modulates the intensity transmitted across the micro disk 102 in the waveguides 114 and 116.

8C shows the intensity versus time of the modulated ER, where the relatively low intensity regions 806 and 808 correspond to the relatively higher refractive index induced in the micro disc 102. Relative intensities can be used to encode information by assigning binary numbers to relative intensities. For example, binary "0" may be represented by a photon signal with low intensities, such as intensity regions 806 and 808, and binary "1", such as intensity regions 810 and 812, It can be represented by photon signals with relatively higher intensities.

)은 도파로(116)에서 송신된다. ER은 마이크로 디스크(102)의 주변 영역으로 감쇄적으로 연결되어 대응하는 변조된 WGM을 생성한다. 주변 영역에서 전파하는 WGM의 강도의 변동(fulctuation)은 전극들(108 및 112) 사이의 대응하는 변동하는 전류를 유도한다. 변동하는 전류는, 컴퓨터 디바이스(902)에 의해 처리되는, 변조된 ER에 인코딩된 동일한 데이터를 인코딩하는 전기 신호이다.9 shows a schematic representation of a first micro resonator system, shown in FIG. 1, operated as a photodetector in accordance with embodiments of the present invention. In this configuration, the bandgap of the quantum wells is selected to be smaller than the source of radiation of the input ER transmitted in the waveguide 116. In addition, a reverse bias can be applied to the electrodes such that the electric field is inside the micro resonator. The incoming ER connected to the micro resonator will be absorbed inside the quantum well to create an electron hole pair. The electric field inside the microring causes the electrons and holes to be separated such that a current is generated at the electrodes 108 and 112. Modulated ER (encoding information)

Is transmitted in the waveguide 116. The ER is attenuatedly coupled to the peripheral area of the micro disk 102 to produce a corresponding modulated WGM. The fulctuation of the intensity of the WGM propagating in the peripheral region induces a corresponding fluctuating current between the electrodes 108 and 112. The varying current is an electrical signal that is encoded by the computer device 902 to encode the same data encoded in the modulated ER.

10A-10K illustrate isometric views and cross-sectional views associated with a method of manufacturing the micro resonator system 100, shown in FIG. 1, in accordance with an embodiment of the present invention. FIG. 10A illustrates a first structure including an upper layer 1002, an intermediate layer 1004, a lower layer 1006, and an etch stop layer 1008 supported by a phosphorus-based wafer. An isometric view of (1000) is shown. Layers 1002 and 1006 may be composed of n -type and p -type III-V semiconductors, such as InP or GaP doped with Si and Zn, respectively. The interlayer 1004 includes at least one quantum well, described above with reference to FIG. 2. The etch stop layer 1008 may be a thin layer of lattice-matched In _{0 .53} Ga _{0 .47} As. Layers 1002, 1004, and 1006 may be "molecular beam expitaxy" (MBE), "liquid phase epitaxy" (LPE), "hydride vapor phase epitaxy" (HVPE), "metalorganic vapor phase expitaxy" (MOVPE), or other suitable It may be deposited using an epitaxy method. 10B shows a cross-sectional view of layers 1002, 1004, 1006, 1008 and wafer 1010.

Next, as shown in the cross-sectional view of FIG. 10C, sputtering may be used to deposit the oxide layer 1012 over the top layer 1002. The oxide layer 1012 may be used to facilitate wafer bonding of the upper layer 1002 onto the substrate 106, as described below with reference to FIG. 10G. Layer 1012 may be SiO ₂ , Si ₃ N ₄ , or another suitable dielectric material that substantially enhances wafer bonding to substrate 106.

10D shows a “silicon-on-insulator” wafer 1014 having a Si layer 1016 on an oxide substrate layer 1018. Silicon waveguides 114 and 116 may be fabricated in Si layer 1016 as follows. A photoresist may be deposited over the Si layer 1016 and the photoresist mask of the waveguides 114 and 116 may be patterned to the photoresist using UV lithography. The waveguides 114 and 116 then use a low pressure, high density etch system that utilizes a suitable etch system, such as "inductively coupled plasma etcher" and a chemical reaction based on Cl ₂ / HBr / He / O ₂ . Si layer 1014 may be formed. After the waveguides 114 and 116 are formed in the Si layer 1016, a solvent may be used to remove the photoresist mask, as shown in FIG. 10E, leaving the waveguides 114 and 116. An oxide layer composed of the same oxide material as the substrate 1018 may be deposited on the waveguides 114 and 116 using liquid-phase, chemical vapor deposition. "CMP (chemical mechanical polishing)" processes planarize the deposited oxide to form the substrate 106 with embedded waveguides 114 and 116, as shown in the cross-sectional view of the substrate 106 in FIG. 10F. It can be used to.

Next, as shown in FIG. 10G, the first structure 1000 is inverted and wafer bonding is used to attach the oxide layer 1012 to the top surface of the substrate 106. Selective wet etching may be used to remove the layer 1010 to obtain the second structure 1020 shown in FIG. 10H. An etch stop layer 1008 may be included to prevent the etching process from reaching the layer 1006. In addition, hydrochloric acid may be used to remove the InP-based wafer 1010 because there is etch selectivity between InP and InGaAs of the etch stop layer 1008.

Next, “reactive ion etching” (RIE), “chemically assisted ion beam etching” (CAIBE), or “inductively coupled plasma” (ICP) etching is performed in the shape of the micro disk 102, as shown in FIG. 10I. Can be used to etch layers 1002, 1004 and 1006. A portion of the layer 1002 adjacent to the substrate 106 is left to form the top surface layer 104.

FIG. 10J shows a cross-sectional view of the micro disk 102 and the substrate 106 across the line 10j-10j, shown in FIG. 10I. The current isolation region 128 is formed in at least a portion of the central region of the micro disk 102 using " inpurity induced disording " and annealing. IID methods are known in the art and they are described in "A quantum-well-intermixing process for wavelength-agile photonic integrated circuits" by EJ Skogen et. al ., IEEE J. of Selected Topics in Quantum Electronics , Vol. 8, No. 4, 2002. The IID mixes the layers 118, 120 and 122 of different compositions implanted with impurities. After annealing, the bandgap of the mixed regions displaces into a relatively larger bandgap. Impurities can be implanted in the desired areas by masking and using standard photolithographic processes.

After the IID, dopants may be implanted into the top layer 118 to form the p − -type semiconductor top layer 118 because the IID will also tend to reduce the doping level of the disordered region. For example, Zn functions as a p − type semiconductor dopant for the top layer 118 composed of InP. As shown in FIG. 10K, the material comprising the first electrode 108 and the second electrode 112 may be deposited by e-beam evaporation, using standard topographical graphics processes. It can be patterned to form the holes 108 and 112. A metal having a p -type dopant, such as AuZn, may be used in the first electrode 108 to obtain a p -type contact, and a metal having an n -type dopant, such as AuGe, may be n -type contact 112. It can be used for the second electrode 112 to obtain a.

11A-11B illustrate cross-sectional views associated with a method of manufacturing a photonic system 500, shown in FIG. 5, in accordance with embodiments of the present invention. Forming the micro disc 102 and forming the waveguides 114 and 116 on the substrate 106 can be accomplished as described above with reference to FIGS. 10A-10I. As shown in FIG. 11A, a material including microring electrode 502 and electrodes 112 and 504 may be deposited and patterned as described above with reference to FIG. 10K. A metal having a p -type dopant may be used in the first electrode 108 to obtain a p -type contact, and a metal having an n -type dopant may be used in the electrodes 112 and 504 to obtain n- type contacts. Can be used. Next, a mask layer can be positioned over the microring electrode 502 and the IID can be used to form the current isolation region 128 in the micro disk 102. After the IID, as described above with reference to FIG. 10J, dopants may be implanted into the top layer 118 to form the p -type top layer 118.

For purposes of explanation, the foregoing descriptions have used specific names to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that no specific details are required to practice the invention. The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations are possible in light of the above teaching. Embodiments are shown and described in order to best explain the principles of the present invention and their practical applications, and accordingly various implementations having various modifications suitable for the particular use of the present invention and those skilled in the art. Make the best use of the examples. It is intended that the scope of the invention be defined by the following claims and their equivalents.

Claims (10)

As a microresonator system 100,
A substrate 106 having a top surface layer 104;
At least one waveguide (114, 116) embedded in the substrate (106) and positioned adjacent to the upper surface layer of the substrate; And
Microdisk 102 having an upper layer 118, an intermediate layer 122, a lower layer 120, a current insulating region 128 and peripheral annnular regions 124, 126—of the micro disk. The lower layer is attached to and in electrical communication with the upper surface layer of the substrate, the micro disk is positioned such that at least a portion of the peripheral annular region is disposed over the at least one waveguide, and the current insulating region is Is configured to occupy at least a portion of the central region of the substrate and has a relatively lower refractive index and a relatively larger bandgap than the peripheral annular region;
Micro resonator system comprising a. The method of claim 1,
First electrodes (108, 502) disposed in said top surface layer of said micro disc; And
At least one second electrode 112, 504 disposed in the upper surface layer of the substrate adjacent the micro disk
Micro resonator system further comprising. The method of claim 2,
And the first electrode further comprises a microring electrode (502) configured to cover at least a portion of the peripheral region of the upper surface of the micro disk. The method of claim 1,
The micro disk,
Upper layer;
Lower layer; And
An intermediate quantum-well layer sandwiched between the upper and lower semiconductor layers
Micro resonator system further comprising. The method of claim 4, wherein
The upper layer (118) further comprises a p − type semiconductor and the lower layer (120) further comprises an n − type semiconductor. The method of claim 4, wherein
The intermediate layer (122) further comprises at least one quantum well. The method of claim 1,
The micro disk 102,
Circular shape;
Elliptic shape;
Any other geometry suitable for supporting whispering gallery mode (WGM)
A micro resonator system further comprising one of the. As a micro disc,
Top layer 118;
Bottom layer 120;
An intermediate layer (122) having at least one quantum well, said intermediate layer sandwiched between said top layer and said bottom layer;
A peripheral annular region (124, 126) comprising at least a portion of said top, middle, and bottom layers; And
A current isolation region 128 including at least a portion of the top, middle, and bottom layers and configured to occupy at least a portion of a central region of the micro disk having a relatively lower refractive index than the peripheral annular region
Micro disk containing a. The method of claim 8,
Wherein the upper layer (118) further comprises a p − type semiconductor and the lower layer (120) further comprises an n − type semiconductor. The method of claim 8,
The micro disk,
Circular shape;
Elliptic shape;
Any other geometry suitable for supporting whispering gallery mode (WGM)
The micro disk further comprises one of.

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